The present invention relates to force-multiplying tools for rotary members, and it relates more particularly to power wrenches for rotating the gate-operating shaft on a railroad hopper car.
Railroad hopper cars have a bottom discharge opening that is closed by means of a sliding gate. The operating mechanism for opening and closing the gate includes a rotary shaft having a free end by which it is rotated. The end of the shaft is provided with an enlarged head or capstan, which has holes extending generally radially through it to receive a pry-bar, and a square portion at the very end to which a hand wrench can be applied or the socket of a power tool connected. Usually the gate is opened by hand using a pry-bar, one end of which is placed in one of the holes in the capstan. A large pipe or monkey wrench can also be applied to the square portion of the capstan in order to complete the opening of the gate once it has been started, or to assist in getting it started. Frequently, it is impossible to open a gate by hand, even when a sledge hammer or other impact tool is used to try to jolt it free. Due to the extreme difficulty encountered in opening gates on many cars, workmen assigned to the job are frequently seriously injured. Furthermore, the connection on the end of the capstan becomes so badly worn that hand and power wrenches can not hold on it and are therefore useless.
Various power tools have been devised heretofore for opening hopper-car gates, but none have been entirely satisfactory because, among other things, they are too heavy and awkward to handle or cost too much to be practical. Furthermore, the capstan extends only a short distance outward of the track and beneath the outer side of the car, making it difficult to get at and to apply the necessary power directly in line with the capstan instead of some distance axially outward of it. Consequently, in all prior power wrenches or force-multiplying tools of which I am aware, the point at which power is applied is located some distance along the axis of rotation from the point at which connection is actually made with the capstan. Such an arrangement makes the tool twist when torque is exerted by it on a capstan, thereby making it extremely difficult to handle and reducing its efficiency considerably.
A primary object of the present invention is to eliminate such misalignment between the point at which power is applied to the force-multiplying device and the point at which the multiplied force is exerted on the capstan. Another object is to provide a force-multiplying device for opening hopper-car gates in which the connection with the operating shaft is made with the periphery of the capstan itself instead of with the wrench engagement surfaces provided, so that positive connection can be made even if the tool-engaging surfaces are badly worn. An important object of the invention is to provide a relatively lightweight portable power wrench for opening hopper-car gates in which the torque required to open the gate is executed within a plane perpendicular to the capstan of the operating shaft of the gate, instead of at some other point axially outward thereof.